Color Transform from one color to another

What node do I use or is there a tutorial did keyframing and or tweening from one color to another? For instance a character getting sick and wanting to transform their face green and to show the transition between the two colors? Or a character eating something something spicy and transforming the colors to red?

I have looked and looked and only see color overrides but no way to transform the colors from one to another in sequence.

This is done using an older version of Harmony but you get the idea and can apply it to later versions.